Help understanding LPC Interiors

Help understanding LPC Interiors

I was able to get the outdoor terrain tiles  and the Boat to work (Examples below) But I am having trouble understanding how the

LPC Interiors are created, I don't understand how https://opengameart.org/content/lpc-walls and https://opengameart.org/content/lpc-floors

are supposed to work... does anyone have any articles or tutorials about how to combine the tiles correctly to generate these interior scenes?